My bike helmet light that I built

Different parts used. Li-ion batteries and copper plumbing caps, Seoul SSC P4 LEDs, reflectors, motor heat sinks, arctic silver epoxy, ...

After installing the LEDs and wiring them up

Mounted light:

Rear close-up:

Light beam in a dark room. Took the picture on auto with no flash. ~400 lumen.

Upgraded the optics to reduce the beam to 80 degrees from 130

Upgraded the power switch

Since the new optics have a dome that sticks out a little, the light reflects off the blue heat sink.

The new beam and the light.

I thought this cable cover would look cool